One look acoustical ceiling tile

ABSTRACT

A family of acoustical ceiling panels for schools, offices, hospitals and other public buildings provides for one consistent look throughout the building while yet provide a range of desired acoustical performances. The family includes a group of substrate mats of a bonded mixture of mineral fiber, glass fiber, and bi-component fibers. Each mat is chosen from a group including a thickness of ¾″, ⅞″ and 1″ depending upon acoustical performance. The group of substrate mats all have an exposed surface chosen from a group including fine texture, heavy texture, medium texture and light texture. The group of mats all have an edge chosen from a group including square, tegular and narrow tegular.

BACKGROUND OF THE INVENTION

When sound becomes noise, people get irritated and stressed. This is not only true in schools, but also in offices, hospitals, and other public buildings. Many scientific and empirical studies have described the impact of poor acoustics. In schools, up to 70% of the consonants spoken by teachers cannot be heard by pupils. In open plan offices, 60% of employees say that noise is the single most disturbing factor. In offices, 70% of employees believed that their productivity would be higher if their environment was less noisy. In offices, normal noise reduces the effectiveness in cognitive tests by 66% compared to the level in quiet surroundings. Sales in a retail shop can increase by 5-10% as a rule of thumb through acoustic improvement measures. In hospital environments, noise control is very important to the recovery of patients as “unwanted sound” can increase heart rate, blood pressure and respiration rate.

Sound waves can travel through any media, which includes air, water, wood, masonry or metal. The type of media through which sound travels determines whether the sound is either airborne or structureborne. Airborne sound is directly transmitted from a source into the air. All sound that reaches your ear is airborne. Some examples of airborne sound are passing traffic, music or voices from an adjacent room, or the noise from machinery and aircraft.

Structureborne sound travels through solid materials, either from direct contact with the sound source or from an impact on the material. All structureborne sound must eventually become airborne sound in order for people hear it, otherwise, the disturbance is felt as a vibration. Examples of structureborne noise are footsteps, door slams, plumbing vibrations, mechanical vibrations and rain impact. Most noise control situations require that both airborne and structureborne sound be considered. Effective sound control addresses both sound paths by controlling, or reducing, noise at the source, reducing paths or blocking noise along its path, or shielding the receiver from the noise.

Sound transmission loss is the decrease in sound energy—expressed in decibels of airborne sound—as it passes through a building construction. The metric used to quantify that reduction is the sound transmission classification, STC. The STC value indicates how well sound is controlled room-to-room, including through walls or through floor/ceiling assemblies.

ASTM E 90 is the standard covering airborne sound transmission class or STC. This is a single number rating that evaluates the efficiency of systems in reducing the transmission of airborne noise. In this class the higher the STC rating the better. The rule of thumb is that a 10 point increase in STC means a decrease in the perceived noise by one-half.

ASTM E 1414 is the standard covering ceiling attenuation class or CAC. The rating is similar to STC but in this case measures the efficiency of a suspended ceiling connected by a common air plenum at reducing airborne noise between two rooms. The higher the CAC number the better.

Impact sound transmission loss is expressed in decibels of airborne sound. This decrease in sound energy is measured after the impact noise that's generated above transfers through the floor-ceiling assembly and is transmitted into the air below. Imagine someone hopping around upstairs, over your head. That's impact sound transmission. It's rated using an impact insulation class number, an IIC number.

The standard for measurement is ASTM E 492. The impact insulation class number, the IIC number, is a single number rating that estimates the impact sound insulation performance of floor/ceiling systems. The number is an estimate of how much the sound energy is reduced. The higher the number, the better the system.

Sound absorption, is the ability of a material to absorb sound waves rather than reflect sound waves. When we talk about absorption, building materials are measured for their noise reduction coefficient, or NRC. There's also a second measurement method to calculate absorption, the sound absorption average, SAA. Fundamentally, sound absorption, or the lack of it, is concerned with controlling sound energy within rooms and enclosed spaces.

Sound absorption of a building material is measured using ASTM C 423. NRC is an arithmetic average (rounded off to the nearest 0.05) of the sound absorption capability of a product at only four frequencies: 250, 500, 1000, and 2000 hertz. These frequencies are representative of the center range of human speech. NRC is a single decimal rating between 0 and 1, used to express the absorption properties of materials. Generally speaking, an NRC of 0.55 is average performance and anything above an NRC of 0.70 is considered good for acoustical ceiling tile systems. The higher the NRC the better the material is at absorbing sound energy.

Also Light Reflectance or LR is of consideration. A LR value is the number designation indicating the percentage of light reflected from a ceiling panel surface in accordance with ASTM E 1477.

Articulation Class or AC is a means of rating the relative acoustical performance of products, such as ceilings, used in open plan office environments. In the open office, the primary source of distracting noise is human speech and a major concern, therefore, is how to prevent intruding speech from distracting coworkers. If there is a general hum or murmur in the space, but no clearly understood words, we can generally “tune this out” as background noise. Speech sounds only become intrusive if the words can be understood. In this type of situation it is difficult not to “listen in” and be distracted (whether you want to listen in or not!).

When evaluating the AC performance, sound is generated by a speaker on one side of a 60″ high partition. Data is collected on the attenuation of sound (how much quieter it is) on the other side of the portion at frequencies from 100 to 5000 Hz (very low pitch to very high pitch). The noise reduction data is then used to calculate the AC value of the product being tested. In calculating AC, the sound reduction that occurs at higher frequencies (>1000 Hz) are treated as more important than those that occur at low frequencies. Why? AC allows us to evaluate how well a product will absorb the noise generated by people talking. Voices generate sound at a wide range of frequencies; vowel sounds occur at low frequency and consonant sounds occur at higher frequency. Vowel sounds only carry loudness. It is the consonant sounds that are most important in speech comprehension. For example, the consonant sounds are the only difference in the words ball, fall, fawn and malt. If a product can absorb most of the consonant sounds, then you cannot tell what the person in the cubicle across the room is saying into their telephone. Again, if you cannot understand the words, the noise is not as distracting.

Ceilings best suited for use in the open office have AC values of 170 or greater. A standard acoustical ceiling (NRC 0.55) will normally have an AC of 150. Non-absorptive materials, such as gypsum board, will have an AC of 120. The highest AC that can be achieved by a ceiling is between 220 and 230.

Examples of acoustic considerations within a building environment are as follows:

High NRC—spaces which sound levels must be kept at a minimum.

open plan offices lobbies/reception areas (HIPAA and FGI requirements)

libraries and classrooms

waiting rooms, nurses' stations (HIPAA and FGI requirements)

neonatal intensive care units (FGI requirements)

any large public space

High CAC—spaces from which sound should not transfer to adjacent rooms.

conference rooms

examination rooms

private offices

classrooms

lobbies

corridors

any large public space

High AC—spaces which require high speech privacy

open plan offices

lobbies/reception areas (HIPAA and FGI requirements)

waiting rooms, nurses' stations (HIPAA and FGI requirements)

restaurants

any large public space

Low AC—spaces that require high sound transmission

front/speakers' area of classrooms or large conference rooms

speakers' podium or orchestral space in an auditorium

Some of the known ceiling panels available are from Armstrong Commercial Ceilings and Walls of Lancaster, Pa.; USG Corporation of Chicago, Ill.; and Certain Teed Corporation of Valley Forge, Pa. They include:

Armstrong (AWI) Panels

Cirrus family—fine textured surface (wet-felted mineral fiber)

Cirrus—available in ¾″; NRC 0.35 and 0.70; CAC 35; LR 0.86

Cirrus High CAC available in ⅞″ only; NRC 0.70; CAC 38 and 40: LR 0.86

Cirrus Open Plan—available in ⅞″ only; NRC 0.75; CAC 35; LR 0.85

Fine Fissured family—medium textured surface (wet-felted mineral fiber)

Fine Fissured—available in ⅝″ only; NRC 0.55; CAC 35; LR 0.85

Fine Fissured High Acoustics—available in ¾″ only; NRC 0.70; CAC 35 and 40; LR 0.85

Fine Fissured Open Plan—available in ⅞″ only; NRC 0.75; CAC 35; LR 0.86

Fine Fissured Ceramaguard—available in ⅝″ only; NRC 0.55; CAC 38 and 40; LR 0.82

Fine Fissured School Zone High Durability—available in ⅝″ only; NRC 0.55; CAC 35; LR 0.85

Fine Fissured School Zone High Acoustics—available in ¾″ only; NRC 0.70; CAC 35 and 40; LR 0.85

Durabrite family—fine textured surface

Optima Open Plan (glass fiber)—available in 1″ and 1-½″; NRC 0.90, 0.95, and 1.00; CAC 26 and not disclosed; LR 0.90

Optima Open Plan (glass fiber with plant-based binder)—available in 1″ only; NRC 0.95; CAC not disclosed; LR 0.90

Optima TechZone (glass fiber)—available in ¾″ and 1″; NRC 0.90 and 0.95; CAC not disclosed; LR 0.90

Ultima (wet-felted mineral fiber)—available in ¾″ only; NRC 0.70; CAC 35; LR 0.86 and 0.90

Ultima High CAC—available in ¾″ only; NRC 0.60; CAC 40; LR 0.90

Ultima Open Plan—available in ¾″ only; NRC 0.75; CAC 35; LR 0.89

Ultima TechZone—available in ¾″ only; NRC 0.70; CAC 35; LR 0.90

Durabrite Washable family

Optima Health Zone (glass fiber)—available in 1″ only; NRC 0.95; CAC not disclosed; LR 0.86

Ultima Health Zone (wet-felted mineral fiber)—available in ¾″ only; NRC 0.70; CAC 35; LR 0.86

USG Panels

Frost family—fine textured surface (cast mineral fiber)

Frost—available in ¾″ and ⅞″; NRC 0.55 and 0.70; CAC 35, 38, and 40; LR 0.83

Frost ClimaPlus—available in ¾″ and ⅞″; NRC 0.70; CAC 36, 38, and 40; LR 0.83

Frost ClimaPlus High NRC/High CAC—available in ⅞″ only; NRC 0.75; CAC 38 and 40; LR 0.88

Mars family—fine textured surface (“X-technology” mineral fiber)

Mars ClimaPlus—available in ¾″ only; NRC 0.70; CAC 35; LR 0.89

Mars ClimaPlus High NRC—available in ⅞″ only; NRC 0.80; CAC 35; LR 0.89

Mars Healthcare—available in ¾″ and ⅞″; NRC 0.70 and 0.80; CAC 35; LR 0.89

Radar family—non-directional fissured surface (water-felted mineral fiber)

Radar—available in ⅝″ and ¾″; NRC 0.55 and 0.60; CAC 33 and 35; LR 0.84 and 0.85

Radar ClimaPlus—available in ⅝″ only; NRC 0.50; CAC 40; LR 0.82

Radar Ceramic ClimaPlus—available in ⅝″ only; NRC 0.55; CAC 33 and 35; LR 0.84 and 0.85

Radar ClimaPlus High NRC/High CAC—available in ⅝″, ¾″, and ⅞; NRC 0.55 and 0.70; CAC 35 and 40; LR 0.84

Radar ClimaPlus High Durability—available in ⅝″ only; NRC 0.55; CAC 35; LR 0.84

Radar ClimaPlus Open Plan—available in ⅞″ only; NRC 0.75; CAC 35; LR 0.84

CertainTeed (CT) Panels

Akutex FT family—fine textured

Ecophon Focus A & A XL (glass fiber)—available in ¾″ only; NRC 0.95; CAC 21; LR 0.85

Ecophon Focus E/24, E/24 XL, E/15, E/15 XL (glass fiber)—available in ¾″ only; NRC 0.90; CAC 23; LR 0.85

Ecophon Focus Dg & Dg XL (glass fiber)—available in ¾″ and 1″; NRC 0.90; CAC not disclosed; LR 0.85

Ecophon Focus Ds & Ds XL (glass fiber)—available in ¾″ only; NRC 0.85; CAC 25; LR 0.85

Ecophon Focus F (glass fiber)—available in 20 mm only; NRC 0.80; CAC not disclosed; LR 0.85

Fine Fissured family—non-directional fissured surface (wet-felted mineral fiber)

Fine Fissured—available in ⅝″ only; NRC 0.55 and 0.60; CAC 33, 35, and 40; LR 0.84

Fine Fissured High NRC—available in ¾″ only; NRC 0.70; CAC 35; LR 0.83

Symphony Reinforced Mat Face (scrim) family—fine textured surface

Symphony f (glass fiber)—available in ¾″, 1″, and 1-½″; NRC 0.80 and 0.95; CAC 22, 24, and 25; LR 0.90

Symphony g (gypsum board)—available in ½″ only; NRC not disclosed; CAC 40 and 42; LR 0.90

Symphony m (wet-felted mineral fiber)—available in ¾″ only; NRC 0.70; CAC 33 and 35; LR 0.90

All of these current non-metallic acoustical panel substrates or mats may generally be described as (1) wet-felted or cast mineral fibers with an organic binder, usually starch-based; may also contain wood pulp/paper fibers and/or inorganic components such as perlite (volcanic glass beads); (2) dry-felted glass fibers with a thermally activated organic binder, usually a formaldehyde compound; (3) ceramic-like inorganic composite consisting of clay, and either mineral fibers or perlite, or a combination of mineral fibers and perlite; (4) gypsum panels (plasterboard or drywall), sometimes reinforced with glass fibers; and (5) composite substrates consisting of two or more of the above substrates laminated together—for example, a layer of glass fiber laminated to a gypsum backer.

Some of the performance features of current non-metallic panel substrates are as follows:

1. wet-felted or cast mineral fibers

advantages—high CAC, high flame resistance, low cost, easy to cut/install

disadvantages—low NRC, low-medium AC, low durability, naturally absorbs moisture, food source for mold

2. dry-felted glass fibers

advantages—high NRC, high AC, inherently mold resistant, lightweight, flexible, durable

disadvantages—low CAC, non-rigid—prone to sagging, high cost

3. ceramic-like inorganic composite

advantages—high CAC, high flame resistance, high durability, moisture resistant—washable, inherently mold-resistant

disadvantages—low NRC, low AC, high cost, difficult to cut/install, heavy, brittle

4. gypsum panels

advantages—high CAC, high flame resistance, low cost, inherently mold-resistant, easy to cut/install

disadvantages—low NRC, low AC, low-medium durability, naturally absorbs moisture

5. composite substrates

advantages—can mix and match substrates to obtain needed performance

disadvantages—high cost and other single substrate non-acoustical problems

SUMMARY OF THE INVENTION

A family of acoustical ceiling panels for schools, offices, hospitals and other public buildings provides for one consistent look throughout the building while yet provide a range of desired acoustical performances. The family includes a group of substrate mats of a bonded mixture of mineral fiber, glass fiber, and bi-component fibers. Each mat is chosen from a group including a thickness of ¾″, ⅞″ and 1″ depending upon acoustical performance. The group of substrate mats all have an exposed surface chosen from a group including fine texture, heavy texture, medium texture and light texture. The group of mats all have an edge chosen from a group including square, tegular and narrow tegular.

A principal object and advantage of the present invention is that the architect or building owner simply chooses exposed surface finish, then an acoustical value for the particular building area and lastly an edge treatment throughout the building.

Another object and advantage of the present invention is that the tile substrate composition and thickness provides for a higher acoustical performances than the competition and prior art in the general NRC ranges of 0.65 to 0.95 while are quite economical to manufacture.

Another object and advantage of the present invention is that the tile substrate composition is able to achieve a combination of better acoustical properties at comparable panel thicknesses than those available from similarly priced or more expensive than competitive panels, along with favorable mechanical properties.

Another object and advantage of the present invention is that the tile substrate composition is able to be “tuned” anywhere within the NRC range of 0.65 to 0.95 by varying the density and thickness. Mineral fiber panels typically obtain an NRC rating of 0.55; but they can range from 0.35 to 0.75. Glass fiber panels typically obtain an NRC rating of 0.90; but they can range from 0.80 to 1.00.

Another object and advantage of the present invention is that the tiles or panels of the present invention obtain a typical CAC rating of 30; but range from 25 to 31 without huge increases in panel thicknesses. Mineral fiber panels typically obtain a CAC rating of 35; but they range from 33 to 40. Glass fiber panels typically obtain a CAC rating in the lower 20s—if the rating is disclosed at all.

Other objects and advantages include that the panels are lightweight, flexible, easy to cut and install; more durable than plain mineral fiber; inherently mold-resistant; more rigid than glass fiber panels—less prone to sagging; less costly than glass fiber panels for comparable performance; and have no formaldehyde, unlike glass fiber panels.

DESCRIPTION OF THE FIGURES

FIG. 1 is a Flow Chart of the production line of the present invention; and

FIG. 2 is a Matrix for the selection of particular acoustical performance, finish and edge detail.

DETAILED SPECIFICATION

The ceiling panel of the present invention is comprised of mat or substrate with a bonded mixture of mineral fiber, glass fiber, and bi-component fibers. FIG. 1 shows the manufacturing assembly of the mat or substrate.

FIG. 2 shows a Matrix by which the architect or building owner selects his ceiling panels to be used throughout his entire building. First the architect chooses surface finish (fine texture, heavy texture, medium texture and light texture) of the panels to be used throughout his building. Next the architect considers the different areas within the building and then chooses the standard performance, mid-range performance or high end performance for each particular building area. Lastly the architect choose edge finish (square, tegular or narrow tegular). In short, the architect simply picks a finish, acoustical value and an edge detail to create his high performance ceilings. 

What is claimed:
 1. A family of acoustical ceiling panels for schools, offices, hospitals and other public buildings that provide for one consistent look throughout the building while yet provide a range of desired acoustical performance, comprising: a) a group of substrate mats comprised of a bonded mixture of mineral fiber, glass fiber, and bi-component fibers each mat chosen from a group comprising a thickness of ¾″, ⅞″ and 1″ depending upon acoustical performance; b) wherein the group of substrate mats all have an exposed surface chosen from a group comprising fine texture, heavy texture, medium texture and light texture; and c) wherein the group of substrate mats all have an edge chosen from a group comprising square, tegular and narrow tegular.
 2. A method of choosing a family of acoustical ceiling panels for schools, offices, hospitals and other public buildings that provide for one consistent look throughout the building while yet provide a range of desired acoustical performance, comprising: a) choosing a group of substrate mats comprising of a bonded mixture of mineral fiber, glass fiber, and bi-component fibers each mat chosen from a group comprising a , ⅞″ and 1″ depending upon acoustical performance; b) choosing for all the group of substrate mats all having an exposed surface chosen from a group comprising fine texture, heavy texture, medium texture and light texture; and c) choosing for the group of substrate mats all having an edge chosen from a group comprising square, tegular and narrow tegular. 